High dosages of oral corticosteroids taken daily for prolonged periods of time can have serious systemic side effects including bone loss ( osteoporosis), increased risk of infections and diabetes and cataracts, thinning of skin, stretch marks, increased facial/body hair growth, acne, fluid retention, weight gain with redistribution of fat (fat deposits on back and face, thinning of limbs), muscle weakness, decreased resistance to infections, stomach ulcers, mood swings, insomnia, suppression of the body's own production of cortisol, etc.
Research studies and clinical trials support the contention that platelet injection therapy is safe. The risks are minimal that any type of complication or negative reaction will occur. Because no foreign objects or substance are being injected into the body, there is no risk of it rejecting the treatment and no disease transmission risks. The only noted risk, and it is a small one, is that the injection might cause some type of infection to develop. This is not unique to platelet injection therapy. Any time a person has an injection, they are at risk for developing some sort of infection.