People Are Megadosing Glycine for Anti-Aging but Is It Actually Safe?

Glycine megadosing has been making the rounds in anti-aging circles, with some people swearing by its benefits for longevity, skin health, and overall well-being. The idea is simple: by taking much higher doses than what’s typically found in food, you’re supposedly giving your body a powerful tool to slow down the aging process. But is it actually safe? And does it deliver on the hype?

Glycine is at the Center of the Longevity Discussion

Glycine isn’t new. It’s a non-essential amino acid, meaning your body can make it on its own. It’s also abundant in many animal-based foods, particularly in connective tissues, collagen, and gelatin. For decades, it has been known for its role in collagen synthesis, neurotransmitter function, and even blood sugar regulation. But recent research has pushed glycine into the spotlight for its potential anti-aging properties, with some people taking anywhere from 10 to 20 grams a day—far beyond what you’d get from diet alone.

Dr. Ken Berry, a Board-Certified Family Physician, points out that modern diets have created a significant glycine gap. “For millions of years, humans ate nose-to-tail, consuming not just muscle meat but also collagen-rich parts like tendons, skin, and bone marrow,” he explains. “Today, most people eat only lean cuts of meat, which are low in glycine and high in methionine. That imbalance is a problem.”

Methionine, another amino acid found in high amounts in muscle meat, has been linked to accelerated aging when consumed in excess. Glycine helps balance methionine, making it a crucial part of longevity-focused nutrition. But how much glycine do we actually need?

How Much Glycine is Enough?

The body naturally produces about 3 grams of glycine daily, and most people consume another 3 grams from food. That adds up to around 6 grams a day, which is enough to keep things running—but not necessarily optimal for longevity. Some experts, including Dr. Berry, suggest that optimal glycine intake might be closer to 10 to 15 grams daily, or even more for individuals with high metabolic demands, chronic illness, or aging-related concerns.

“If you’re young, healthy, and metabolically flexible, your glycine needs are probably modest,” says Dr. Berry. “But if you’re older, dealing with autoimmune issues, or recovering from injury, your glycine requirements skyrocket.”

A growing number of people have turned to glycine supplementation to bridge the gap, often in the form of collagen powders, gelatin, or pure glycine powder. But some take it even further, pushing doses past 20 grams a day in hopes of getting a stronger anti-aging effect. That’s where things get more complicated.

The Argument for Megadosing Glycine

The reasoning behind megadosing glycine comes down to three main benefits:

Collagen Synthesis and Skin Health

Glycine makes up about a third of collagen, the protein responsible for keeping skin firm and joints strong. Since collagen production declines with age, supplementing with glycine could, in theory, slow down wrinkles, sagging skin, and joint deterioration. “People taking high doses of glycine often report noticeable improvements in their skin’s elasticity and hydration,” says Dr. Berry. “It’s one of the few supplements with solid evidence behind it.”

Glutathione Production and Antioxidant Support

Glycine is a key component of glutathione, the body’s master antioxidant. As we age, glutathione levels decline, making us more susceptible to oxidative stress and inflammation. Some studies suggest that increasing glycine intake can boost glutathione production, potentially protecting against age-related diseases. “Glutathione is your body’s natural defense system,” Dr. Berry notes. “Glycine is a bottleneck in its production, so if you’re not getting enough, your ability to fight oxidative stress takes a hit.”

Methionine Balance and Longevity

High methionine intake, particularly from muscle meats, has been linked to shorter lifespans in animal studies. Restricting methionine has been shown to extend lifespan, but that’s not practical for most people. Glycine, however, can counteract the negative effects of methionine overload. “Excess methionine without enough glycine is like pressing the gas pedal without brakes,” Dr. Berry explains. “You need glycine to maintain balance and prevent accelerated aging.”

Is It Safe to Take High Doses of Glycine?

The short answer: probably, but we don’t have long-term studies to say for sure. Glycine is generally well tolerated, and there’s no established upper limit. Some people taking 10 to 20 grams per day report better sleep, improved skin, and reduced joint pain. Others notice no difference at all.

But megadosing anything comes with potential risks, even if it’s a seemingly harmless amino acid. Here’s what to keep in mind:

• Digestive issues: Large doses of glycine can cause loose stools, bloating, or nausea in some people, particularly when taken all at once.
• Blood sugar regulation: Glycine has been shown to lower blood sugar levels, which might be beneficial for some but problematic for those prone to hypoglycemia.
• Neurotransmitter effects: As an inhibitory neurotransmitter, glycine has calming effects on the nervous system. While this can improve sleep, it might also lead to excessive drowsiness or brain fog if taken in very high amounts.
• Unknown long-term effects: We simply don’t have decades of research on what happens when people take 20+ grams of glycine daily for years. The body is complex, and more isn’t always better.

Dr. Berry advises caution when it comes to megadosing. “There’s no doubt that glycine is beneficial, but taking extreme doses without clear data to support it is always a gamble,” he says. “More isn’t always better—it’s about balance.”

How to Get More Glycine Without Going Overboard

If you’re looking to increase glycine intake without pushing into unknown territory, there are plenty of practical ways to do it:

Eat more glycine-rich foods. Bone broth, chicken skin, pork rinds, and gelatin are excellent sources of glycine and come with other beneficial nutrients.

Incorporate collagen supplements. Hydrolyzed collagen powders typically contain about 3 grams of glycine per 10-gram serving.

Use glycine powder strategically. Adding 5 to 10 grams of glycine powder to tea or yogurt is an easy way to increase intake without overloading your system.

Most importantly, glycine should be part of a well-balanced diet rather than a magic bullet for longevity. It’s one piece of the puzzle, but it’s not the whole picture.

Glycine has a lot going for it when it comes to anti-aging benefits, but megadosing beyond 10 to 15 grams per day is still uncharted territory. While it’s unlikely to be harmful for most people, the long-term effects of extremely high doses remain unknown. Instead of chasing an arbitrary number, a more balanced approach—through diet, collagen, and moderate supplementation—might be the smarter way to go.