Collagen is a critical component in skin health, and as such, it has been touted as a miracle cure for pretty much everything that ails the skin. Among the many blemishes and issues your skin accumulates over the years, stretch marks are some of the most hated.
So what are stretch marks, and can collagen help you with them?
What Causes Stretch Marks
Stretch marks are exactly what they sound like. They're marks on your skin that appear when your skin stretches. They tend to appear when your skin is forced to stretch quickly, such as during puberty, pregnancy, rapid weight changes, or muscle training.
Stretch marks can also appear if you're taking a corticosteroid for a long period of time, or if you have a disease such as Cushing's Disease or Marfan Syndrome. It's also theorized that hormonal changes can be responsible for stretch marks, since some people get them and others do not, despite similar degrees of tissue changes.
When stretch marks first appear, they may have an appearance similar to wounds or irritation. They can be red, pink, purple, or dark brown, depending on your natural skin color. Over time, they fade in color, typically to a lighter shade of your natural skin color similar to a scar.
Stretch marks are more than just color; since they are fissures caused by your skin stretching, you can compare them to a canyon along a fault line in the earth's crust. They tend to have a slightly raised or swollen feeling when they first appear, due to inflammation. As they mature, they settle into slight depressions in the skin.
What Collagen Does for Skin
Collagen is a protein found in your skin. It's essentially the glue that holds your skin cells together and the scaffold upon which your skin is built. Your body synthesizes collagen constantly, using it to repair skin damage, grow new skin, and keep your skin elastic and healthy.
People often choose to take collagen supplements as a way to help aid their skin and maintain a youthful appearance. This can help if you're eating collagen, in the form of bone broth, a collagen supplement, or an additive in smoothies. It will not help if it's an ingredient in skin creams or other topical applications. 
Consuming collagen may or may not be better than simply consuming protein from other sources. Your body has to digest and break down whatever you eat, and synthesize fresh collagen from the food or supplements that you consume. Eating collagen ensures that you have those raw materials to make fresh collagen, though you can get the same from balanced protein sources. Just make sure you're getting enough Vitamin C along the way; it's a crucial nutrient used for the synthesis process.
As your body ages, your natural ability to create more collagen slows down. This is combined with the aging of your skin, making wrinkles and other blemishes form. You can potentially slow this aging process down by making sure you're consuming enough collagen, but studies have not yet proven how effective this may be.
Can Collagen Help with Stretch Marks?
The question most of you are here to have answered is "can collagen help with stretch marks?" The answer is maybe, not also not really.
Stretch marks are scars. They are scars caused by the damage of your skin expanding rapidly, faster than its elasticity allows.
By consuming more collagen before doing whatever it is that causes stretch marks, you may be able to infuse your skin with more collagen and improve the elasticity of the epidermis. If this is the case – and scientific evidence is scarce for this treatment, since it's difficult to test when everyone reacts differently – you may be able to minimize or prevent stretch marks from forming before they form at all.
This means starting a daily collagen supplement before weight training, before starting a regular corticosteroid cream, or before getting pregnant.
However, collagen will not do anything to stretch marks you already have. As far as your body is concerned, the skin has stretched, it was scarred to repair the damage, and that's it. Scars are not repaired by the body. Scars ARE the repair. Your body will not put more collagen into the stretch marks, because as far as your body is concerned, the stretch mark is fine where it is.
How to Prevent Stretch Marks
As we mentioned, stretch marks are a scar. There are essentially two ways to attempt to prevent stretch marks. You can either avoid doing the things that cause stretch marks, or you can prepare your skin for stretching.
Preparing your skin to stretch typically means taking more collagen, but you can also take other ingredients that stimulate the elasticity of your skin. This means:
- Quit smoking. Smoking destroys both collagen and elastin in your skin, making it much less resilient to damage. This is why lifelong smokers tend to have many more wrinkles than non-smokers of equivalent age.
- Use sunscreen. Sun damage breaks down collagen and elastin in the skin, leading to wrinkles and damage. Sun rays can also cause blemishes and skin cancer, so it's always a good idea to wear a suitably strong sunscreen whenever you plan to spend an extended amount of time out in the sun. Remember, this doesn't just apply to summer fun; sun damage can occur even on cloudy days or in winter as well as summer.
- Eat a healthier diet. A healthier diet does two things to help prevent stretch marks. First, it infuses your entire body with vitamins, minerals, amino acids, and other components that keep it healthy and resistant to damage. Second, it helps to reduce the chances of abrupt weight gain. A healthier diet is lower in calories and thus doesn't store as much fat, meaning less weight gained and less stress on your skin.
- Get plenty of sleep. Your body does most of its work repairing itself while you sleep, since waking hours devotes more energy to things like moving and thinking. Making sure you get plenty of restful sleep helps keep your skin youthful.
- Use skincare products. Skincare products that include retinol or retinoid, in particular, are excellent. Unlike collagen, retinoids penetrate the skin and can help it maintain its elasticity. Other vitamins and minerals can also be helpful. Plus, these skin creams often include some level of SPF protection and can serve double-duty as part of your sunscreen regimen as well.
- Drink more water. When you're dehydrated, your skin dries out and begins to sag. Drinking more water – yes, more than you think you need – helps keep your skin hydrated and healthy.
In large part, the prevention of stretch marks means preparing skin to be as elastic as possible. It also means avoiding the cause of stretching in the first place.
We already mentioned eating a healthier diet up above, to help prevent weight gain. This is important, but sometimes it's not effective on its own. You may also need to exercise regularly to maintain your current weight. Remember, as you age, your metabolism decreases. There's no real way to speed up your metabolism at its baseline, so you need to take progressively more action over time to maintain your youthful figure.
As with most things in beauty, an ounce of prevention is worth a pound of cure. Damage done to your skin compounds as you age, and sooner or later, you WILL experience some form of blemish or sign of aging. It's just a matter of how soon it happens and how bad it is.
Warning: One of the major causes of stretch marks is pregnancy. While you can (obviously) avoid getting pregnant to avoid those stretch marks, that's not possible if your goal is to have a child and start a family. Avoid retinoids at all cost if you're pregnant. This means products that contain Vitamin A, Retinol, Retin-A, Retinoic Acid, and Tazaratene. Excessive amounts of Vitamin A in the body have been linked to birth defects in a fetus.
While there's little evidence to suggest that vitamin A skin cream can cause birth defects, it's better to be safe than sorry.
How to Treat Stretch Marks
If you're already developing stretch marks, or you've had them for years and you want to get rid of them, unfortunately, there's not much you can do. Again, stretch marks are scars, and scars are not easy to get rid of.
If your stretch marks are still fresh – that is, in the red, itchy phase, not the mature light-colored scar – you may be able to lighten their appearance. We're going to recommend several different options, but keep in mind that some work for some people and not others. You may be particularly resistant to certain kinds of treatment, or they might be more or less effective than they are for other people. Keep an open mind and realize that every person is different.
Option 1: Using lotion or skin cream meant to lighten stretch marks. While there are thousands of these products on the market, you should look for a product with a retinol or retinoid vitamin in it. 
Some products with collagen in them do not penetrate the skin, so be skeptical about their efficacy. To quote the American Academy of Dermatology:
- "Use the product on early stretch marks. Treatment seems to have little effect on mature stretch marks.
- Massage the product into your stretch marks. Taking time to massage the product gently into your skin may make it more effective.
- Apply the product every day for weeks. If you see results, they take weeks to appear."
In other words, treatments need an extended amount of time to take effect. You should spend several minutes gently massaging your cream of choice into your stretch marks. Some evidence suggests that the physical manipulation of the scar-to-be helps reduce its appearance by the time it matures. This may work for stretch marks as well as other scars, like post-surgical scars.
If you've tried a retinoid before and want something a little stronger, you can consider talking to your dermatologist about a prescription treatment. In particular, Hyaluronic Acid might be effective in reducing the appearance of new stretch marks. Again, mature stretch marks do not really respond to treatment.
While a commercial product may work, evidence suggests that home remedies do not. No studies have yet been conducted that prove almond oil, cocoa butter, vitamin E, or olive oil work on stretch marks. It's better to go with the tried and tested vitamin A preparations instead.
Option 2: Conceal your stretch marks. While you may not be able to get rid of them, concealing stretch marks can help you feel better about your appearance. You have two options here: a makeup concealer or self-tanners. Tanning will actually make stretch marks worse, because they do not tan, so as your skin gets darker, the lighter stretch marks stand out even more. However, a self-tanner can be applied to the stretch marks to hide them.
Option 3: Surgical treatments. A dermatologist may be able to perform one or more skin treatments to help reduce the appearance of stretch marks. Chemical peels, microdermabrasion, laser therapy, and RF or Ultrasound treatments all may be able to reduce the overall appearance of stretch marks. None of them can get rid of stretch marks entirely, however.
If you find yourself trying and failing to treat stretch marks with creams and lotions, and your pre-emptive collagen has not helped, you may consider talking to your dermatologist about more robust treatment options. Otherwise, you may just need to resign yourself to this common, harmless sign of aging.
