Best Glutathione Supplement

One thing a lot of supplement users have in common is the desire to live longer and be healthier. In surveys conducted by the National Center for Health Statistics, you'll find the most widely reported reasons for supplementation are to improve or maintain overall health and to target specific issues like heart health and age-related changes.1 If your motivations are similar, a single supplement to address several health concerns could be just the thing you want to streamline your regimen.

Glutathione may be one such supplement. Often referred to as the "master antioxidant," glutathione is a naturally occurring substance the human body needs to protect its cells from oxidative stress. As a supplement, it has low toxicity and a relatively high potential to safeguard you against harmful health outcomes to your brain, heart, and a host of other areas.15

Glutathione supplements should meet some basic parameters to be maximally beneficial, and not all of them clear the bar. In this guide, we discuss the four best glutathione supplements we've identified, assess their merits, and go deeper into the roles that glutathione plays in human health.

Check out our summary of recommendations for the quickest rundown. Then read further to understand how we reached our conclusions.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

Writing this guide to the best glutathione supplements started with comprehensive research on the subject of glutathione itself. Among other things, we sought to understand glutathione's role in the body, how it works, and what benefits it could impart as a supplement. Then we scoured the glutathione supplement market to identify products whose qualities aligned with what we'd found in our research. Those are the products we ordered and tried for ourselves.

Additionally, like all health-related content on this website, this guide was thoroughly vetted by one or more members of our Medical Review Board for accuracy and will continue to be monitored for updates by our editorial team.

Evaluating the market's best glutathione supplements involved five criteria related not only to the products themselves but also to the brands that make them:

• Effectiveness
• Safety
• Cost
• Ease of use
• Customer service

Each of our recommendations had something to offer in each criterion, even when it didn't rise to the very top in the category.

Effectiveness

Winner: Codeage Liposomal Glutathione

By "most effective," we mean "most effective for most people." Codeage Liposomal Glutathione fits the bill because it provides a versatile dose of a branded glutathione through a delivery system found to increase bioavailability.

Codeage’s combined dosage and serving size hit a sweet spot in which it can provide the desired health outcomes while also giving room to titrate down as needed. Clinical studies on oral glutathione often use doses of 500-1,000mg — as in a four-week trial in 2011 and another in 20192 3 — but we know that effective doses have ranged as low as 250mg, like in a six-week trial of Setria (the same brand used in Codeage) in 2015.4 Because Codeage delivers 500mg of Setria across two capsules, you can take the lower dose if you’re concerned about the safety issues that may correspond with higher doses,5 or you can take the full recommended serving size if you’re not. Of course, our other recommendations also let you titrate as needed, but to potentially less effect.

Life Extension and Doctor's Best provide clinically relevant glutathione doses, but they lack Codeage’s liposomal delivery. Liposomal delivery entails encapsulating compounds in microscopic lipid particles to protect the active ingredient as it travels through the digestive tract. Therefore, it helps ensure that your body absorbs the maximum possible amount of glutathione.19 Because Life Extension and Doctor’s Best aren’t liposomal, less of their glutathione is likely to get into your system.

Quicksilver Scientific allows plenty of room for titration, but its base dose of 100mg is on the low side. Although its orobuccal route of administration (i.e., through the tissues lining the mouth) leads to greater absorption, even the lowest orobuccal dose used in studies is 50mg higher.22

Safety

Winner: Codeage Liposomal Glutathione

Oral glutathione is generally safe for most people. If any side effects arise, they tend to be minor and temporary — itching, rash-like patches, tiredness, and transiently high liver enzyme levels. To approach toxic levels, a person would have to take around 32.5g of glutathione,6 which is over 64 times more than what you'd get with even the highest-dosed options among our recommendations.

For the most part, then, we have to look at a brand's manufacturing practices to determine the safety of its glutathione supplement, and for the following reasons, Codeage shines just a little brighter than the others on that front:

Truth be told, we had a tough time choosing the safety winner, as Life Extension and Quicksilver also perform strongly in terms of quality controls. Life Extension third-party tests its raw materials, too, and Quicksilver performs one of the largest allergy panels we've encountered. But after a point-by-point assessment, we determined that Codeage does more to accommodate a larger user population.

The only one of our recommendations that may present a higher risk for adverse effects is Doctor's Best Glutathione + Milk Thistle. Part of it has to do with its milk thistle, which has numerous drug-drug interactions and can cause anaphylaxis in people allergic to certain plant families. We discuss these matters in the product's dedicated section later in this guide.

Cost

Winner: Life Extension Glutathione

Even after you account for the shipping cost for non-subscription orders below $50, Life Extension Glutathione, at $23.25, is around $5 less than the second-most affordable glutathione supplement on our list (Doctor's Best) and more than $20 less than the most expensive (Quicksilver Scientific). And if you subscribe, the cost difference is even starker since the price drops to $18.68 and you get free shipping.

The per-serving cost is likewise the lowest on the list, as the table below illustrates. (The per-serving costs are for the label-recommended doses. Shipping costs are included where applicable.)

Doctor’s Best isn’t that much higher, so it remains a comparatively budget-conscious option for people who want additional liver support. The same could be said for Quicksilver Scientific if you feel the easier route of administration and higher overall serving volume are worth a little more up front.

Ease of use

Winner: Quicksilver Scientific Glutathione

Depending on what survey you look at, something like 10-40% of the population has trouble swallowing pills — a condition known as pill dysphagia.7 8 For them, no capsule is an easy go.

That's why Quicksilver Scientific Glutathione is our pick for the easiest-to-use glutathione product. It's a liquid supplement, so there's nothing to cause physical discomfort. You just administer 1mL, hold it in your mouth for a while, and then swallow.

Sure, it needs to be refrigerated, but the bottle is tiny and hardly takes up any shelf space. Also, the liquid is flavored, and the flavor may not appeal to everyone, but our testers rather liked it. One of them described the Cacao Mint flavor as "sort of a minty cereal."

Customer support

Winner: Life Extension

We had tough competition in this criterion, as nearly all of our top recommended glutathione brands demonstrated superb customer support. Life Extension pulled ahead of the others for three reasons:

Codeage's and Quicksilver's teams were excellent in their own rights, providing responses within five and 90 minutes, respectively. Codeage did so through its online chat function, but it doesn’t seem to have a direct email line. Quicksilver’s answer came through email, but it lacks an online chat function.

The only company that was lacking in top-tier customer support was Doctor's Best. It took about 24 hours to receive the initial response, which only said that someone would get back to us at some point. We received a second response two days later saying that our question was transferred to another department. Finally, on day five, we received a definitive answer to our question. On the one hand, in terms of giving us accurate information, the team at Doctor's Best gave us their best, and we appreciate that. On the other hand, we wish the answer had come sooner.

Here’s a quick side-by-side comparison of our top glutathione supplements in key consumer decision factors, including cost, serving quantity, and dosage. (Shipping and taxes are excluded.)

Glutathione (γ-l-glutamyl-l-cysteinyl-glycine) is the body’s most dominant tripeptide, found in every cell in the body. It also occurs naturally in various foods, including asparagus, avocado, cucumber, green beans, and spinach.9

A tripeptide is a molecule that comprises three precursor amino acids, which in this case are cysteine, glutamic acid, and glycine. Peptides in general are hugely important because they’re fundamental to numerous physiological and biochemical processes, such as energy metabolism, wound healing, and cellular communication.10

Glutathione is also an antioxidant, a substance that protects the cells from oxidative stress and damage. Oxidative stress occurs when the body has too many unstable molecules called pro-oxidants — free radicals and reactive oxygen species (ROS). Because they're unstable, they can take electrons from other cells or react negatively with the molecules in a cell, setting off a chain reaction that terminates in apoptosis, or cell death.11

Oxidative stress can stem from various causes, such as smoking, drinking, environmental pollution, exposure to sunlight, and mental/physical stress.12

Although the body needs pro-oxidants, they can cause several detrimental health effects when present in overabundance without enough antioxidants to counter them, such as:13

• Cancer
• Rheumatoid arthritis
• Kidney diseases
• Cardiovascular diseases
• Neurological diseases
• Respiratory diseases
• Psychological disorders
• Age-related degeneration

The importance and benefits of glutathione

Glutathione is known as the "master antioxidant" because it plays a critical role not only in scavenging free radicals and ROS but also in supporting the body's other antioxidants. It can, in fact, recycle antioxidants such as vitamins C and E14 — that is, return them to antioxidant capacity even after they've neutralized a pro-oxidant — further helping your body to keep its pro-oxidants and antioxidants in balance. (Remember, a state of oxidative imbalance makes a person more susceptible to numerous diseases.)

Therefore, having an ample supply of glutathione in the body is critical for maintaining health. More specifically, it may be able to prevent or improve conditions related to glutathione depletion, including but not limited to:15 16

• Alzheimer's disease
• Parkinson's disease
• Chronic obstructive pulmonary disorder (COPD)
• Asthma
• Hypertension
• High cholesterol
• Atherosclerosis (a hardening of the arteries)
• Eyesight or hearing impairments
• AIDS-related weight loss
• Symptoms of cystic fibrosis

Some research even points to glutathione's ability to impart cosmetic benefits, such as improved skin elasticity and reduced wrinkles.17

Glutathione supplements work by adding glutathione to the body. The more glutathione in circulation, the better the body is at combating oxidative stress and preventing the associated diseases.

In supplements, glutathione exists in its reduced form. Here, "reduced" refers to a reducing agent, which stands in opposition to an oxidizing agent. So, when we say glutathione is reduced, we mean it can remove oxygen or ROS — hence its being an "antioxidant" — after which the glutathione becomes oxidized. Meanwhile, an enzyme in the human body called glutathione reductase recycles oxidized glutathione back into its reduced state,18 allowing the tripeptide to continue carrying out its biochemical functions.

Glutathione supplements are normally oral supplements, and there's some controversy about oral glutathione’s bioavailability. Some researchers, like the ones behind a 2011 study, contend that digestive enzymes oxidize or destroy orally administered glutathione and prevent "significant intact absorption."2

Fortunately, there are some common solutions to the absorption problem, as explained in the following subsections.

Liposomal glutathione

A liposomal supplement is one that has been encapsulated in fat molecules called phospholipids. These phospholipids protect the contents from degradation in the digestive tract so they can pass through the hostile environment and enter the bloodstream.19

We can compare a couple of studies to determine the effect on bioavailability that liposomal delivery can impart. In 2011, for example, researchers who administered 1,000mg per day of non-liposomal glutathione found "no significant changes were observed in biomarkers of oxidative stress" in participants after four weeks.2 In contrast, a 2019 study of identical length administered liposomal glutathione at 500-1,000mg doses and saw significant decreases in oxidative stress biomarkers plus improvements in immune system markers.3

Two of our top recommended glutathione supplements are liposomal, by the way:

• Codeage Liposomal Glutathione, our recommendation for most people
• Quicksilver Scientific Glutathione, our top liquid glutathione supplement

Branded glutathione

Glutathione supplements often use one of two branded versions of glutathione that are formulated to improve absorption: Setria or Opitac.

Because they're patented properties, it's unclear how these branded forms can withstand the digestive environment, but both have demonstrated their potential to do so in clinical studies.

Orobuccally administered glutathione

Orobuccally administered glutathione is transported through the tissues lining the mouth and cheeks, allowing it to circumvent the hostile gastrointestinal environment altogether.

A 2015 study on the subject concluded that compared to "gastroresistant tablets" of identical dosage (e.g., liposomal and branded forms), 250mg of orobuccal glutathione led to "much quicker absorption and a considerably higher bioavailability" while producing "rapid onset of action."21

Another 2015 study comparing sublingual and oral routes of administration found the sublingual group exhibited higher total and reduced glutathione levels in plasma. The researchers noted that 150mg of sublingual glutathione was equivalent to 450mg of oral glutathione22 — approximately the amounts used in clinical studies of liposomal versions.

Among our recommendations, only Quicksilver Scientific qualifies as an orobuccally administered glutathione, as the label directions say to hold the liquid in the mouth for 30-90 seconds before swallowing.

While glutathione supplements are broadly suitable for almost anyone who wants to increase their body's capacity to combat oxidative stress, they can best serve individuals who wish to prevent, delay, or alleviate specific chronic health conditions associated with glutathione depletion:15

• Neurodegenerative disorders such as Alzheimer's and Parkinson's
• Respiratory diseases like asthma and COPD
• Cardiovascular diseases like hypertension and high cholesterol
• Age-related diseases like cataracts, macular degeneration, and hearing impairment
• Immune diseases like HIV and AIDS
• Liver disease
• Cystic fibrosis

Additionally, because the goal is to reduce oxidative stress, people who are regularly exposed to ROS-generating compounds (e.g., smoke, alcohol, and sunlight)23 might consider adding glutathione to their supplement rotation, at least to help counter the effects of oxidative stressors.

Glutathione isn't a surefire preventive or treatment for the above concerns, but it can bolster your body's natural antioxidant defenses against certain disease onset or progression to a degree.

For example, in a 2011 review published in Molecular Basis of Disease, the researchers concluded that glutathione administered to a living subject may protect the brain against amyloid beta, a protein known to accumulate in the brains of people with Alzheimer's disease.24

For another example, in the case of people with HIV, clinical studies have shown that preserving high enough glutathione levels is important for decreasing mortality and that glutathione administration can improve survival rates.25

So, while glutathione isn’t some miracle supplement, it can be part of a larger ecosystem of self-care. In addition to supplementation, users should proactively do whatever else they can to mitigate oxidative stress in their bodies. At the very least, that means limiting exposure, when possible, to those ROS-generating compounds that we’ve mentioned.

Also, as with any supplement, you should speak with your doctor to determine whether glutathione is right for you.

Who are they not for?

Despite being a naturally occurring tripeptide in the human body, glutathione isn't suitable for everyone as a dietary supplement. The three main populations that should avoid supplementation are:

There's one final population that might rethink adding glutathione to their supplement rotation: people who already get enough glutathione. If you eat a diet rich in foods like asparagus, avocado, and spinach, you may already have enough dietary glutathione to supplement your body's natural production. Taking more glutathione shouldn't hurt, but you'd be spending money and effort on a health pursuit you don’t need to follow.

Glutathione supplements are generally considered safe for anyone who isn’t pregnant, breastfeeding, or hypersensitive. A 1987 study on mice determined oral glutathione to be nontoxic,27 and a 2017 toxicity study (also on mice) found that glutathione's LD₅₀ (the amount of a substance needed to kill 50% of all test animals in one dose) was 5g/kg.6 An equivalent toxic dose for an 80kg human would be 32.5g, which is more than 32 times the highest amounts used in clinical studies.

Yet some adverse effects are possible at lower doses, although they’re temporary and not life-threatening. The same 2017 study referenced above reported the following side effects in some participants who received 250mg of oral glutathione:6

• Pruritis (itching)
• Macular erythema (rash-like red patches on the skin)
• Red spots on the skin
• Tiredness
• Transaminitis (high liver enzyme levels in the blood)

Additionally, specific glutathione supplements may pose more safety concerns than others. The potential dangers usually come down to a company's operational processes, but sometimes (as with Doctor's Best), the product includes additional ingredients with higher side effect profiles than glutathione. We cover such variables in the dedicated brand sections that follow.

Best glutathione supplement for most people

Codeage Liposomal Glutathione delivers 500mg of Setria glutathione across two relatively small capsules (less than 2cm in length). The dosage is within the clinical range used in a successful 2019 study,3 and the liposomal delivery increases bioavailability by protecting the active ingredient as it travels through the harsh environment of your digestive tract.19

For people who don’t need an entire 500mg to yield glutathione’s health effects (e.g., those who are sensitive or follow a plant-based diet), Codeage makes it easy to titrate the dose down to one capsule. A 250mg half-dose happens to correspond with the amount used in a 2015 randomized, controlled trial that saw blood glutathione levels increase by 17%.4

Apart from having a solid clinical dose, Codeage Liposomal Glutathione is soy-free, gluten-free, and vegan. Moreover, Codeage as a company adheres to high quality-control standards that involve:

• Testing raw ingredients for safety
• Third-party testing of finished products
• Providing certificates of analysis on request

Pricing and shipping

A bottle of Codeage Liposomal Glutathione costs $39.99 as a one-time purchase, plus $6.95 for standard shipping. That comes to around $1.56 per dose with the two-capsule serving size recommended on the label, but it drops to $0.78 per dose with a one-capsule serving. A subscription drops the base price to $33.99 with free shipping — a 15% discount — which corresponds to $1.13 per two capsules and $0.57 per one.

Your delivery intervals are limited to one, two, and three months. Seeing as a bottle contains either 30 or 60 servings, we can appreciate that your options align with daily use quantities.

Normally, you can expect your order to arrive in 2-5 business days. Ours hit a delay in transit owing to a major snowstorm, so it exceeded the estimated delivery range by a day. But hey, still not bad.

International customers may be happy to know that Codeage delivers overseas via third-party providers, though generally without free shipping.

Return Policy

Codeage has a 30-day money-back guarantee that lets you try and return a product for a refund, though with some tight restrictions:

• For single orders, the money-back guarantee applies only to one item and one order per household. If your order contains more than one supplement, only one of them qualifies for a refund; thereafter, your account is no longer eligible for a refund on any product.
• For bundles, full refunds apply only if you haven’t opened any of the items. If you have opened an item, you can be refunded only the difference between the amount you paid and the amount you would’ve paid for a single item. For example, if you’d bought a Liposomal Glutathione two-pack for $60 and returned one of the bottles, you’d be eligible for a refund of around $20; that’s because you would’ve paid $39.99 for the single bottle you used, and the remainder amounts to $20.01. (Our example here is hypothetical. Codeage does not currently offer its Liposomal Glutathione in a bundle.)

What’s more, you are the one responsible for return shipping, so deduct that value from your refund amount.

Given the time range and limitations, we’d say Codeage’s return policy is the worst on our list. Even Quicksilver Scientific, whose 30-day policy is of equal length, has a separate satisfaction guarantee that lasts 45 days from the purchase date.

Customer support

Inquiries to Codeage can be made via telephone or online chat.

We reached out to Codeage’s customer support through the online chat widget displayed in the lower right-hand corner of every page on its website. The answer we got was direct and succinct, and the turnaround time was about three minutes — a blink compared to many companies’ support teams. The only brand on our list that outperformed Codeage in customer support was Life Extension.

Best glutathione supplement for people on a budget, best customer support

Life Extension Glutathione delivers its marquee ingredient in a clinically relevant 500mg dose. It's not a liposomal form of glutathione, but it is Opitac, which has demonstrated rapid absorption through the intestinal epithelial cells.20

You'll see on the label that Life Extension also provides 80mg of calcium, which is helpful. In a study published in 2000 in the International Journal of Surgical Investigation, the researchers found that rats whose cells were perfused with calcium preserved more of their cellular glutathione and hence "demonstrated significantly lower oxidative stress and an improved liver function."28 The findings suggest that Life Extension Glutathione not only adds glutathione to your body but also may help you maintain the glutathione you already have.

On the operational front, Life Extension is commendable for third-party testing both its raw materials and its finished products. That way, the company can be sure its products contain exactly what the label states, without the risk of contaminants and heavy metals. Also, like Codeage, Life Extension provides certificates of analysis to anyone who requests one.

Pricing and shipping

Life Extension costs $23.25 as a one-time purchase. A subscription costs $18.68 (20% off, the highest discount on our list). In either case, it's the lowest-priced glutathione supplement among our top recommendations.

Subscriptions and orders above $50 ship free to the United States. For one-time orders below the $50 threshold, standard shipping is $5.50.

You can choose subscription delivery intervals from one to 12 months. You'll be hard-pressed to find a more diverse range. Of course, a bottle contains 30 servings, so daily users shouldn't need anything beyond a one-month interval unless they have multiple bottles per shipment.

Standard shipping should take 3-5 days. Our order arrived on the third day.

Life Extension does ship internationally. Orders to Canada cost a flat rate of $19.50. For overseas orders, airmail rates apply.

Return policy

Life Extension has a 365-day return policy that takes effect from the purchase date. If there's another supplement company somewhere with a better policy, we aren't aware of it.

You have two ways to initiate a return:

Note that some products may require a $5.50 fee for a prepaid shipping label.

Customer support

We've dealt a lot with Life Extension customer support over the years, and they've always been speedy, responsive, and helpful. Even compared to Codeage and Quicksilver Scientific, both of whose support teams are terrific, Life Extension's team is superlative.

Case in point: Unlike the other brands on our list, Life Extension offers three modes of contact — email, telephone, and chat widget. Using the chat widget, we connected with a representative within ten seconds and received a satisfactory answer within 30 seconds.

Best glutathione supplement for liver support

Doctor's Best Glutathione + Milk Thistle uses the same Setria-branded glutathione, and at the same dose, as Codeage: 500mg.

As the label shows, Doctor’s Best also has two other ingredients: milk thistle and selenium. Here’s what each one can contribute to your health:

One thing we wish Doctor's Best would do is provide more details about its quality control processes. The company does conduct third-party tests for quality, purity, and consistency, but it's unclear whether they're done on raw materials, finished products, or both. The website isn't forthcoming about allergen testing, either. That's not to say Doctor's Best doesn't do allergen testing or take other measures to ensure consumer safety, only that the information isn't readily available.

Pricing and shipping

Doctor's Best Glutathione + Milk Thistle costs $33.99 as a one-time purchase and $32.29 as a subscription. The subscription discount is just 5%, which is the lowest on our list, but the price is low enough either way to be the second-most affordable (after Life Extension).

Shipping is free for all orders above $30, so one bottle of Glutathione + Milk Thistle easily gets you over the threshold.

Like most of our other recommendations, your subscription delivery intervals are limited to just one, two, or three months. As with Codeage, the intervals align with daily use quantities.

Shipping is almost as fast as Life Extension. Our order arrived on the fourth business day after the purchase date.

All orders are fulfilled by iHerb, which ships internationally to over 180 countries. Check the iHerb website to verify that your country is among the international shipping territories. In fact, buying this product directly from iHerb can save you a bit of money.

Return policy

Doctor's Best has a 60-day refund policy from the purchase date, which is good enough to be the second-best policy on our list. It's certainly better than Codeage’s 30-day policy and Quicksilver's 45.

Initiating a return and refund involves sending an inquiry form through the Doctor's Best contact page. Should you want to return your product, we hope your customer service experience is more expedient than ours was.

Customer support

We were happy to have received an initial response within 24 hours of our inquiry, but the message told us only that someone else would get back to us eventually. The second response came two days after the first, and it notified us that our issue was being transferred to another department. It wasn't until the fifth day after we sent our question that we finally received an answer to our question. The turnaround wasn't bad — it’s admittedly better than some companies we’ve dealt with over the years — but it was significantly slower than the other brands in this guide.

To the support team's credit, the answer was direct, succinct, and complete. Had Doctor's Best condensed the response time to a 24-hour turnaround, we would've considered its customer support to be top-tier. As it is, we think it could use a little improvement.

Best liquid glutathione supplement (easiest to use)

Quicksilver Scientific Glutathione is a liposomal supplement and the only liquid glutathione product in our guide. As such, it enters your body through two routes:

• Orobuccally: As you hold the liquid in your mouth for 30-90 seconds, the glutathione diffuses through the tissues lining your mouth. Studies have shown this route of administration to provide significantly increased bioavailability.21 22
• Orally: After 30-90 seconds, you swallow the liquid. Whatever you ingest travels through your gastrointestinal tract and gets absorbed in the same way as Codeage, Life Extension, and Doctor's Best. Meanwhile, the liposomal form helps increase bioavailability as well.

The glutathione dosage here is just 100mg per two-pump serving, and even with the liposomal/orobuccal administration, that's on the low end. A 2015 study used 150mg of a similarly administered form of glutathione, which is a good 33% higher than the Quicksilver dosage.22 But there's a silver lining in that Quicksilver is easy to titrate up as needed, and just an additional pump will get you up to that 150mg threshold (though at the expense of shrinking its use life).

As a liquid supplement, Quicksilver Scientific is the easiest-to-use product in our guide since users don't have to contend with swallowing pills. It may pose a different sort of hurdle, though, and that's the taste. Some people may enjoy the taste (our testers certainly liked the Cacao Mint flavor), but others may not. Those in the latter camp should know that the taste does linger a bit, so if that's a dealbreaker, one of the capsule supplements may be more to their preference.

Safety-wise, Quicksilver Scientific is impressive because, on top of third-party testing, it performs an extensive allergy panel that covers more than 20 allergens:

What's more, its liposomal glutathione is vegan, so users can be assured of a cruelty-free product.

Pricing and shipping

Quicksilver Scientific Glutathione costs $45 as a one-time purchase and $40.50 as a recurring subscription.

Subscriptions are delivered every one, two, or three months. A bottle contains around 50 servings, so the delivery intervals are a bit awkward for daily users who follow the label-recommended serving size: A one-month interval leaves you with a surplus every month, and a two-month interval leaves you with a deficit. A three-pumps-a-day regimen gets you closer to a 30-day use life, but then you still have a three-day surplus.

Normally, we might suggest ordering from Amazon for a more accommodating delivery schedule, but Quicksilver appears not to offer a subscription option for Liposomal Glutathione through its Amazon storefront. The best workaround is to purchase directly from Quicksilver and pause your subscription as needed — which is inconvenient, to say the least.

Quicksilver Scientific has a free-shipping threshold set at $99. If your order is below the threshold, even with a subscription, you’ll have to add a shipping fee based on the order’s weight and destination. Our order cost $7.95 to ship via UPS Ground — the highest shipping cost among our recommendations — bringing our pre-tax total to $52.95.

The shipping is lightning-fast, though. Our order arrived in two business days, beating not only the other brands on our list but also the estimated shipping time we'd been given (3-7 days).

Quicksilver doesn't ship internationally but has distribution centers in several countries. Customers outside of the United States or Puerto Rico should refer to Quicksilver's distributor list to make their purchases.

Return policy

Non-refrigerated Quicksilver products can be returned for a refund within 30 days of receipt as long as they're unused and unopened. Unfortunately, because Quicksilver's liquid glutathione is a cold product, it's not eligible for a return.

The company does have a separate satisfaction guarantee, however. If you aren't satisfied with your Quicksilver Scientific Glutathione, you can request a refund within 45 days of the purchase date. The guarantee applies only to products purchased directly through the Quicksilver Scientific website.

Though not as generous as Life Extension's or Doctor’s Best’s policy, the 45-day guarantee is better than what you get from Codeage.

Customer support

Like Codeage and Life Extension, the customer support team at Quicksilver Scientific is superb. Though they were just a bit slower, no more than 90 minutes passed from the time we sent our email inquiry to the moment we received a response. Here, too, the answer we received was direct and complete, requiring no follow-up.

From our research, we've identified two viable alternatives to glutathione supplementation. One is another sort of supplement altogether, and the other is a lifestyle modification.

NAC supplements

N-acetyl cysteine (NAC) is another amino acid and critical antioxidant. It's known as a prodrug of cysteine, meaning that it converts to cysteine in the body. Remember that cysteine is one of the precursors to glutathione, so the idea is that ingesting NAC as a supplement indirectly increases your glutathione levels.

Like glutathione, NAC has low bioavailability. According to a 2021 review, "[Less than 10%] of the intact molecule reaches the plasma and tissues."35 With that in mind, you'll want to look for a brand that maximizes absorption through some mechanism like a liposomal delivery system.

Another thing to bear in mind is that some animal studies have cast doubt on NAC's ability to stimulate glutathione production and even called into question its overall safety. For example, a 2005 study found that NAC administration failed to raise glutathione levels in rats,36 and a 2022 study on mice suggested that it may promote the metastatic spread of certain cancers.37 While it’s true that animal studies don't directly translate to human outcomes, they're still important to consider when choosing a supplement meant to support your health and wellness.

Diet

Glutathione is a substance you can obtain through dietary sources. Besides the foods we mentioned earlier — asparagus, avocado, cucumber, green beans, and spinach — a 2019 review notes that a glutathione-supported diet should include the following vegetables and fruits:9

There remains the question of how much of these foods you should eat and whether dietary glutathione is optimal for everyone. It's an ambiguity acknowledged by the review's authors, who state that more research is needed to clarify optimal amounts and to identify "sub-groups of individuals most likely to respond to particular nutrients or foods."

Speaking with a doctor is your best first-line action to determine whether you could benefit from swapping dietary glutathione for a supplement, or vice versa.