There is information about how it can help diabetes at http://www.gojimedia.com.au/info/diabetes.php – in particular it says, "Goji has been used in China for the treatment of diabetes for many years, and its polysaccharides have been shown to help balance blood sugar and insulin response. It also contains betaine, which can prevent fatty liver disease and vascular damage often seen in diabetics. "

I take Goji in a juice form, which is really pleasant taking (my sister’s 17 month old daughter takes it quite happily). I buy mine online from http://soundhealthwa.freelife.com
References :

Blood Sugar :-

Very efficacious remedy for blood sugar Syzygium J.Q(Mother Tincture) 4 hourly,8 – 10 drops

Diabetes mellitus with emaciation Uranium Nit 3X 4 hourly

When diabetes is due to nervous weakness; apathetic condition; general weakness; specially in men Acid-Phos 1X, or 6X, 4 hourly

Complaints with excessive thirst; wasting disease; melancholy; constipation; in sad persons Natrum Mur 12X or 30X, 4 hourly

Intercurrent remedy Medorrhinum 200 fortnightly (3 Doses).

General debility; thirst for large quantity of water; profuse and frequent urination; recurrent boils with much itching; diabetic itching Cephalandra Ind. Q (Mother Tincture) 4 hourly, 5 -10 drops

Dryness of mouth,thirst increased; frequent urination at night; urine profuse; weakness after passing urine; general debility; pruritus vulvae without eruptions Gymnema Syl. Q(Mother Tincture) 4 hourly, 5 – 10 drops

Dryness of mouth without thirst. Feels thirsty for large quantity of cold water at night; involuntary urination. Weakness in legs; better rest and pressure Sulphonamide 30X, 4 hourly

Sugar In Urine :-

Well proven indian drug Cephalandra Ind.Q(Mother Tinture) 4 hourly, 5 – 10 drops

Head remedy Syzygium J.Q(Mother Tincture) 4 hourly, 5 -10 drops

Sugar in urine; fidgety feet Zincum Phos.30X 4 hourly

Sugar in urine; urine copious; emaciation, patient ill tempered Tarentula Hisp 30X or 200X 4 hourly (3 Doses)

With great emaciation; craves for icy cold water Phosphorus 30X or 200X 4 hourly (3 Doses)

The proven indian drug called ‘Gur Mar’ Gymnema Syl.Q(Mother Tincture) 4 hourly, 5 – 10 drops .
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Take the remedy which is similar to your symptoms.
No side effects or complications if taken as directed, please do not exceed the given dosage and under any circumstances do not try to mix any remedies and avoid Chocolates, Mints, Coffee, Red Meat, Alcoholic and Carbonated drinks, Spicy Rich Food while taking any Homeopathic remedies, and keep the medicines away from direct sunlight, heat strong smells and perfumes and do not store them in the fridge.
Curing without any side effects or Complications Thats the Beauty of Homeopathic Medicine (Cures Par Excellence)

Take Care and God Bless you.
References :
Homeopathic Practitioner