Younger TRS Tissue Rejuvenating System Versus Younger Regenerative Exosome Serum

Our skin makes fewer of them as we age. This is a big part of why older skin heals slower and looks less bouncy.

The idea behind putting them in skincare is to "top up" the supply from the outside.

"Conditioned media" sounds mysterious but it's basically just leftover broth.

They're made in a lab where scientists grow human skin cells (fibroblasts) in a nutrient liquid. These cells release a cocktail of helpful proteins into that liquid as they live and grow.

Then, these cells are filtered out and the ingredient is the "conditioned" liquid now full of secreted goodies.

So what does neonatal mean here? It just means the original cells came from newborn tissue (usually donated foreskin), which tend to be younger, more active, and better at pumping out growth factors than adult cells.

Technically, this isn't one single ingredient, it's a mix of dozens of active molecules working together, including:

Studies find growth factor conditioned media can help with:

The evidence behind this ingredient is pretty solid too (and not just marketing).

A 24 week study of a fibroblast conditinoed media serum showed measurable improvements in the look of photodamaged skin, and these results were backed by actual skin biopsies rather than just before/after photoshoots.

And a broader review that pulled together many growth factor studies came to a similar conclusion: they generally help with fine lines, texture, firmness, and are well-tolerated.

It's also worth knowing the caveat that the review pointed out most of these serums also contained peptides, antioxidants, and exosomes.

The honest answer is there isn't a tidy "use at 1-2%" number the way there is for something like niacinamide.

This is because conditioned media isn't a single molecule. Brands add it as a percentage of a finished formula so that number is all over the map.

The serums built around it usually advertise very high levels (~50%) while others just use a splash. And the individual growth factors floating inside are actually present in very tiny amounts (think nano/micrograms per gram).

Here's one regulatory anchor point: the FDA has approved a wound healing gel that uses a pure growth factor at 0.01% (100 micrograms per gram). This shows the active growth factors themselves work at very low concentrations.

So the "50%" numbers you see on labels refer to the diluted broth and not the pure proteins.

The single most important thing to understand growth factors is that they are very fragile.

Dr. Zoe Draelos wrote this about them for Dermatology Times:

Independent lab work backs up the fragility.

Many growth factors lose a big chunk of their activity within a day or two sitting in water at room temperature and this is why smart formulating matters so much. Airless pumps, water-free formulas, and cool storage all help the ingredient survive long enough to do something. It's also a green flag if a brand can show real stability testing.

None of this means growth factor serums don't work; plenty of people get lovely results. It just means the formulation and packaging are doing a lot of the heavy lifting.

You may have heard a worry that growth factors "feed" skin cancer because their whole job is to encourage cells to multiply (this is called mitogenic activity).

It's a fair question to ask so here's the actual picture.

The theoretical concern is real enough that dermatologists take it seriously. There IS a hypothetical worry that they can encourage the wrong cells to grow in skin that already has sun damage or pre-cancerous spots.

Due to this, the cautious advice is to check with your dermatologist before using growth factor products if you have psoriasis, a history of skin cancer, or a lot of pre-cancerous sun damage.

Now the reassuring side:

There has been no documented pattern of growth factor products causing skin cancers despite millions of units sold over many years.

A large safety review of pure PDGF (one of the growth factors in these blends) found it to be non-toxic, non-mutagenic, and non-carcinogenic across decades of medical use. This is including repeated daily application to open wounds.

And a dermatology review specifically looking at topical EGF found no evidence that it stimulates cancer cells to grow (partly because these proteins are large and mostly stay near the surface).

The bottom line for a healthy person with no specific risk factor:

Growth factor conditioned media has a strong track record and is generally considered safe and well tolerated.

But be sure to loop in your dermatologist first if you have psoriasis, active or past skin cancer, or heavy sun damage. This is not because it's proven dangerous but because it's a sensible precaution while the long-term research keeps building.

The US allows human-derived growth factors so Human Neonatal Fibroblast Conditioned Media appears on labels.

In the EU, human-cell-derived ingredients are banned in cosmetics. EU products use plant-derived alternatives (barley is a common one) to get a similar effect.

Because hydrolyzed hyaluronic acid is smaller in size, it can slip past your outermost layer of skin more easily than full-sized HA.

Most formulations will combine all sizes to get the best of both worlds.

Typical usage levels range from 0.01-1%. Any percentage higher than 2% might become goopy and tacky.

This ingredient offers promising benefits, but it is relatively new and more evidence is needed to prove its efficacy. The manufacturer claims this ingredient:

A study from 2022 found this ingredient helped protect skin against damaged from UV exposure (though this should not replace your sunscreen!).

The lysate in the ingredient name refers to a fluid that forms from breaking down the cell membrane.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.

One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.

Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.

Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.

The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.

Most leave-on skincare keeps it at the lower end, often between 0.5-1%.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!