Tendonitis vs. Tendinosis: What’s the Difference?

Tendonitis and Tendinosis

Tendonitis is the inflammation of the tendon resulting from micro-tears that happen when the tendon is overloaded with too much weight or loaded too quickly. Tendonitis shows very evident signs of inflammation with cells invading the area to carry out the healing of the tendon and may be red, swollen or hot.

On the other hand, tendinosis is represented by degeneration of the tendon’s collagen in response to chronic overuse (even at benign levels of force) without allowing the tendon time to heal. The chronic nature of this injury means inflammatory cells and active inflammation do not respond to the tissue’s demands.

This pathology is noted by the following findings:

  • Immature type III collagen vs. type I – The tougher type I collagen is replaced in a non-effective pattern by type III collagen that weakens the tendon and exposes it to further damage.
  • In order to help the repair process the body starts to lay down new blood vessels and nerves to the area. However, the added vessels typically do not end up carrying any blood just congesting the area further and the nerves just cause pain.
  • The changes above result in an increase in the bulk of the tendon and represents a significant loss of tendon strength.



It is important to differentiate the pathology because it changes the treatments and the timelines for prognosis. Tendonitis care consists mostly of anti-inflammatory medication, rest and deep tendon massage to reduce adhesions during the inflammatory and healing process. The timeline for this injury varies from several days to 6 weeks depending on chronicity.

The treatment of tendinosis mostly utilizes physical therapies to combat the pain and weakness. Research suggests that, “tendons require over 100 days to make new collagen,” so the prognosis for tendinosis should be longer than tendinitis, ranging from 6-10 weeks for acute to 3-6 months for chronic.

Suggested physical therapies include:

  • Exercises emphasizing eccentric muscle contractions – These contractions are thought of as “negatives,” during which the muscle is contracted as it is lengthened. For example, slowly lowering a weight or your body to the ground.
  • Deep friction massage – Rubbing across or around the area of the tendon stimulates cells called fibroblast to increase activity for collagen production to repair the tendon.
  • Blood platelet replacement or Platelet rich plasma (PRP) – Since there’s no inflammatory process present in the tendon, the body doesn’t know to repair itself.  Here, physicians take blood and separate the cells and growth factors located in blood plasma. Once they have “platelet rich plasma,” they inject it back into the tendon to stimulate healing.
  • Sclerosant agents or high tendon injections – This therapy is aimed at decreasing the excessive neural growth that accompanies the formation of new incompetent blood vessels in order to decrease pain.
  • Extracorporeal shock wave therapy – This is the method of using high frequency sound waves to decrease the excessive neural and vascular growth in to the tendon.
  • Nutrient supplementation – Adding vitamin C, manganese or zinc to your diet have all been shown to be integral to the synthesis of collagen and may be beneficial.

It may be as important to note that the use of non-steroidal anti-inflammatory drugs (ex: ibuprofen) or corticosteroids should be avoided since they can inhibit collagen growth, even though they can provide short term relief from pain.

In conclusion, tendinosis is incredibly more common than true tendonitis and may respond better to therapies that do not focus on the reduction of inflammation. Tendinosis is more challenging to recover from, but there are numerous options being researched to clarify the best interventions to return individuals to activities.


Bass, Lmt Evelyn. “Tendinopathy: Why the Difference Between Tendinitis and Tendinosis Matters.” International Journal of Therapeutic Massage & Bodywork: Research, Education, & Practice 5.1 (2012)

Kardouni, Joseph. “Neovascularization Prevalence in the Supraspinatus of Patients With Rotator Cuff Tendinopathy.” Clinical Journal of Sport Medicine 23.6 (2013)

Khan, JM. “Overuse Tendinosis, Not Tendinitis Part 1: A New Paradigm for a Difficult Clinical Problem.” Physical Sports Medicine 25.5 (2000)

Rees, J. D., M. Stride, and A. Scott. “Tendons – Time to Revisit Inflammation.” British Journal of Sports Medicine 48 (2014)