Are There Any Side Effects of Taking Collagen?

Whether you’ve only just heard about the amazing benefits of collagen or you’re already deep into your research, you might be wondering about any potential side effects of collagen supplements.

After all, a magical supplement that can help with the appearance of fine lines and wrinkles, as well as general skin health – it sounds like there should be a catch, right? (Spoiler: there isn’t!)

Well, in this article, we will talk through both the potential positive and negative side effects of taking collagen.

Let’s jump right in!

*This article was reviewed by our senior scientist, Dr Dave Reilly, in June 2025

What's in our marine collagen supplements?

To better understand any potential collagen negative effects (as well as the benefits!), let’s first take a look at the ingredients in our marine collagen supplements.

And you’ll no doubt be pleased to hear that we only use the best quality ingredients to avoid any adverse collagen side effects. For example, our type 1 marine collagen is derived from sustainably-farmed tilapia and pangasius fish, and our suppliers follow strict BRC guidelines.

What’s more, we believe that type 1 marine collagen is the highest quality collagen available , surpassing collagen sourced from chicken, cows, or pigs. 

To ensure there are no negative side effects of our collagen supplements, we also regularly test for allergens. As such, we can confirm that our product does not contain shellfish, molluscs, or nuts. Absolute Collagen is also free from dairy, gluten, soy, wheat, and lactose – and it does not contain any cholesterol or fat. Bear in mind, however, that marine collagen is derived from fish, so it is not suitable for those with fish allergies or those following a vegan diet . 

So, in short, Absolute Collagen is completely safe to take and has no collagen negative effects. But of course, if you do have any concerns about marine collagen side effects, be sure to consult your doctor or healthcare provider.

Are there any negative side effects of collagen supplements?

While we can of course vouch for our own marine collagen supplements, there are so many other types of collagen on the market. It’s only natural that you’d want to know about any potential collagen negative effects that you might experience.

Well, have we got some good news for you!

Collagen is a protein naturally produced within the body, and there are no documented negative collagen side effects when taking additional supplements to boost production . There’s also no issues around taking collagen while pregnant – in fact, the extra protein can have some benefits for the development and growth of muscles.

However, certain brands or manufacturers might combine collagen with other ingredients that could pose a risk. That’s why it’s always important to read the ingredient list carefully before making a purchase.

Can collagen cause bloating?

It’s only a very small minority of people, but some have reported feeling bloated or heavy as a side effect of taking collagen.

However, we’ve got even more good news: this collagen side effect shouldn’t be an issue with our marine collagen supplements!

In our collagen sachets, you get 8,000mg of marine collagen – which is the optimal amount of collagen that your body can absorb, so there’s no excess to digest. We also hydrolyse our collagen , breaking the molecules into collagen peptides , which are much smaller and easier to digest. 

Can collagen powder cause gastritis?

There’s currently no strong evidence to suggest that collagen powder causes gastritis – which is when the lining of your stomach becomes inflamed or irritated. If anything, taking collagen in small, consistent doses, either with our liquid collagen or powder sachets, is unlikely to irritate your stomach at all.

That said, everyone’s digestive system is different. If you’ve got a sensitive stomach or a history of gastritis, it’s always worth checking the full ingredients list and speaking to your GP about how your body might respond.

Just remember, our collagen powder has a neutral taste, so you can mix it into food or drinks in a way that works best for you – gentle and easy!

Can collagen powder cause diarrhoea?

Again, this isn’t a common issue. However, for a very small number of people, taking too much collagen (especially on an empty stomach) could potentially cause a digestive upset, including diarrhoea.

The good news? Both our powder and liquid are designed to be taken daily in a single, pre-measured 8,000mg dose – so you don’t have to worry about overdoing it. Plus, because it’s hydrolysed collagen , the smaller peptides are easier on your gut and more readily absorbed.

To help avoid any potential digestive issues, we always recommend mixing your collagen powder with food or drink rather than taking it alone. We’ve certainly got loads of collagen recipe ideas you can try!

What happens when you stop taking collagen?

@absolutecollagen What really happens when you stop taking collagen? 🤔 Skin Expert @drsophieshotter is here to break it down for you. Now who's taken their Absolute Collagen today? Let us know below👇 #skinexpert #collagen #collagenfacts #howcollagenworks #collagenscience #supplementsthatwork #howdoescollagenwork ♬ original sound - absolutecollagen

Don’t worry, there are no withdrawal effects when you stop taking collagen supplements. However, your body will gradually return to its natural collagen production levels – which is less than ideal as we age!

Over time, the benefits you’ve been enjoying – like the reduction in the appearance of fine lines and wrinkles – can start to fade. That’s why it’s so important to continue taking collagen every day once you start your subscription; consistency is key!

What are the positive side effects of collagen supplements?

Now we’ve covered off the minimal collagen negative effects and (hopefully!) put minds at ease, let’s talk about some of the positive side effects of collagen supplements.

But we don’t want you to just take our word for it – we want to let our lovely Absoluters’ success stories speak for themselves:

1. Absolute Collagen side effects on skin

Collagen is secreted by many different cells, but predominantly by skin and connective tissue cells. In the dermis, collagen helps to form a fibrous network, upon which new cells can grow, and collagen is also necessary for the replacement of dead skin cells. Over time, the body’s natural levels of collagen decrease as production slows, leading to the skin’s structure weakening, evidenced by the fine lines and wrinkles that we associate with getting older.  

However, many Absoluters have noted the positive collagen side effects on skin, including Jayne and Kerry:

"From the first week I noticed my skin (was) much softer and definitely more supple and hydrated" -Kerry

2. Absolute Collagen side effects on nails

he natural collagen in our bodies is a key component in maintaining strong, healthy nails, supporting the structure of the nail bed. It makes sense, then, that one of the signs of collagen deficiency as we age is a vulnerability to nail breakages and slow growth. 

Well, our Absoluters have reported loving the positive side effects of collagen supplements for their nails! They have reported their nails not only growing faster, but also looking healthier and stronger, as Lynn attests to below:

"Only used this for 2 weeks and WOW my nails are no longer brittle and splitting!!" -Lynn

3. Absolute Collagen side effects on hair

You might not realise it, but our bodies’ natural production of collagen is a key building block of healthy hair. It supports hair to not only grow faster, but thicker and healthier, too.

So, as we age and lose our natural stocks of collagen, we notice signs of ageing in the hair such as thinning, loss of colour, and shedding. However, lots of our Absoluters have reported their hair appearing thicker, glossier, and noticeably longer as side effects of our collagen supplements:

"I love my collagen sachets and have really noticed a difference in the thickness of my hair, it was always so fine but it has at last got slightly thicker so thank you." -Alison

Whether you want to learn more about the positive side effects of collagen supplements or still have some questions about collagen negative effects, we’d love to hear from you ! Alternatively, you can start shopping for our marine collagen supplements today, if you feel ready to start your Absolute Collagen journey.