From our mid-20s onwards, collagen production naturally begins to decline. Research suggests we lose around 1% of our collagen each year, and this decline can accelerate during menopause, periods of stress and as part of the natural ageing process.
So how do you know if your collagen levels are declining? Here are 12 common signs of collagen deficiency and what you can do to support healthy collagen production.
What is collagen deficiency?
True collagen deficiency is rare, but collagen decline is a natural part of ageing. Over time, the body produces less collagen and the quality of existing collagen also decreases.
This gradual reduction can affect many tissues throughout the body, leading to visible and less visible signs of ageing.
1. Fine lines and wrinkles
One of the earliest and most recognisable signs of declining collagen is the appearance of fine lines and wrinkles.
Collagen helps provide skin with structure, firmness and elasticity. As collagen levels fall, skin becomes thinner and less resilient, making wrinkles more noticeable.
2. Loss of skin firmness
Have you noticed your skin doesn’t “bounce back” quite like it used to?
Collagen plays a major role in skin elasticity. Reduced collagen production can contribute to sagging skin around the jawline, cheeks and neck.
3. Dry or dehydrated skin
Healthy skin relies on both collagen and hydration. As collagen declines, the skin’s ability to retain moisture may also be affected, resulting in skin that feels drier, rougher or less radiant.
4. Joint discomfort and stiffness
Collagen is a key component of cartilage, the tissue that cushions your joints. Lower collagen levels may contribute to joint stiffness, reduced flexibility and discomfort, particularly during exercise or everyday movement.
5. Slower muscle recovery
Collagen isn’t only found in the skin and joints. It also plays an important role in muscles and connective tissues. As collagen production declines, recovery after exercise or physical activity may take longer.
6. Weaker tendons and ligaments
Tendons and ligaments rely heavily on collagen for strength and flexibility. Reduced collagen production may affect mobility and resilience, particularly as we age.
7. Thinning hair
Hair health is influenced by many factors, but collagen helps support the scalp and surrounding structures that contribute to healthy hair growth.
Declining collagen may be associated with hair that appears thinner or less robust over time.
8. Brittle nails
If your nails seem weaker, split easily or grow more slowly than before, collagen decline may be one contributing factor. Collagen helps support the structures that contribute to strong, healthy nails.
9. Slower recovery from injuries
Collagen plays a critical role in tissue repair and wound healing throughout the body. Whether it’s a minor strain, a bruise or a more significant injury, reduced collagen production may contribute to slower recovery.
10. Changes in digestive health
Many people are surprised to learn that collagen is also found in the digestive tract. Collagen helps support the structure of the gut lining, making it an important component of overall digestive wellbeing.
Leaky gut syndrome, in particular, is linked to a collagen deficiency. Your intestines have tight junctions, which help you absorb nutrients. However, a leaky gut means that other particles can slip through the gap, causing infection and inflammation.
Collagen plays a significant role in repairing intestinal walls. Therefore, having enough collagen in your body is essential to rebuilding these damaged tight junctions.
11. Increased bruising
Collagen helps provide strength and structure to blood vessels and connective tissues. As collagen levels decline, the skin and underlying tissues may become more fragile, making bruising more noticeable or causing bruises to take longer to heal.
12. Reduced flexibility and mobility
Collagen is a major component of tendons, ligaments and connective tissues. As collagen production declines with age, some people notice increased stiffness, reduced flexibility and a feeling that movement is less fluid than it once was.
What causes collagen decline?
Several factors can accelerate collagen loss:
- Ageing: Collagen production naturally decreases with age, beginning in our mid-20s.
- Menopause: The decline in oestrogen during menopause can significantly impact collagen production. Research suggests women may lose up to 30% of their skin collagen in the first five years after menopause.
- Sun exposure: Ultraviolet (UV) radiation is one of the biggest external causes of collagen breakdown.
- Smoking: Smoking generates oxidative stress that damages collagen and elastin fibres.
- Poor diet: Low protein intake and inadequate vitamin C consumption can affect collagen production.
- Stress and poor sleep: Chronic stress and poor-quality sleep may contribute to accelerated ageing processes throughout the body.
Can you test for collagen deficiency?
There is currently no simple blood test that accurately measures overall collagen levels throughout the body.
Instead, declining collagen is usually identified through physical signs such as changes in skin elasticity, joint health, recovery, hair quality and overall tissue resilience.
How can you increase collagen naturally?
While ageing cannot be stopped, there are several ways to support collagen production:
Eat adequate protein: Collagen is made from amino acids, so consuming sufficient protein is essential.
Increase vitamin C intake: Vitamin C is required for normal collagen formation. Without it, the body cannot effectively produce collagen.
Prioritise sleep: Many of the body’s repair and renewal processes occur during sleep.
Protect your skin from excessive sun exposure: Daily sun protection can help reduce collagen degradation.
Exercise regularly: Resistance training helps support muscles, bones and connective tissues as we age.
Consider collagen supplementation: Hydrolysed collagen peptides provide amino acids that the body can use as building blocks for collagen production. At Rejuvenated, our Collagen Shots combine hydrolysed marine collagen with vitamin C, hyaluronic acid and antioxidants in a science-led formula designed to support healthy ageing and wellbeing from within.
Collagen is about more than skin
While collagen is often marketed as a beauty supplement, its role extends throughout the body.
Collagen helps support:
- Skin health and hydration
- Bones and connective tissues
- Joints, tendons and ligaments
- Muscles and mobility
- The digestive system
- Blood vessels and cardiovascular structure
This is why supporting collagen production is not simply about looking younger - it's about maintaining strength, resilience and wellbeing as we age.
Published clinical studies
A growing body of clinical research has demonstrated the benefits of collagen supplementation for skin hydration, elasticity, joint health and healthy ageing. Below is a selection of published studies exploring the role of collagen peptides in supporting the body’s natural collagen production and connective tissues.
1. Hydrolysed collagen is absorbed and utilised by the body
A review published in Nutrients explains that hydrolysed collagen is broken down into peptides and amino acids, which are absorbed and can stimulate fibroblasts - the cells responsible for producing collagen, elastin and hyaluronic acid in the skin.
2. Collagen supplementation is associated with increased collagen density and synthesis
A systematic review of oral collagen supplementation found evidence of increased dermal collagen density and improvements in skin elasticity and hydration, suggesting that the body is using the supplied peptides as building blocks for collagen-rich tissues.
3. Meta-analysis of randomised controlled trials
A 2025 meta-analysis of 23 randomised controlled trials involving 1,474 participants found that collagen supplementation significantly improved skin hydration, elasticity and wrinkles compared with placebo.
4. Clinical evidence using 10g collagen daily
A clinical study using 10g of collagen peptides daily for 56 days demonstrated significant improvements in skin hydration, firmness and elasticity.
5. Significant improvement in skin quality in just 60 days
In a 2024 clinical study conducted under dermatologist supervision, Rejuvenated Collagen Shots were shown to significantly improve skin quality in just 60 days of daily use. The study also confirmed subjective improvements in skin appearance, nail strength, hair health, and even sleep quality.
The bottom line
Collagen is the protein that helps hold us together. As production naturally declines with age, the effects can be seen not only in our skin but throughout the body.
Supporting collagen production through nutrition, lifestyle and targeted supplementation can help maintain healthy ageing, mobility, hydration and wellbeing for years to come.
Frequently Asked Questions
What are the first signs of collagen deficiency?
Fine lines, reduced skin elasticity, dry skin and joint stiffness are often among the earliest signs of collagen decline.
At what age does collagen begin to decline?
Collagen production typically begins to decrease from our mid-20s onwards.
Can collagen deficiency be reversed?
While collagen decline is a natural part of ageing, healthy lifestyle habits and collagen supplementation may help support the body’s natural collagen production.
Does taking collagen actually work?
Research suggests that hydrolysed collagen supplementation may support skin elasticity, hydration and overall skin appearance when taken consistently.
Should I take collagen with vitamin C?
Yes. Vitamin C is essential for normal collagen formation and is one of the reasons it is included in many advanced collagen formulations.
